GRANNY'S NIGHTMARE CHOPPER BIKE
You know what really irritates the heck out of me? I drive all the way out to the dump, pay my five bucks to get in, and the only bikes laying around are those goofy granny bikes from the late 1970s. Dog, what's the deal? I need some new parts! OK, enough whining, it's payback time. A real chopper artist can chop any bike, even this crusty old codger cruiser. In fact, the more I looked at the bike, the more I thought it would be a sweet ride. Check out all that chrome, look at that long spindly frame, yeah, I could make this happen.
Look at the end result... one cool retro style chopper!
Normally, I do not even bother with these frames because of their "lugged" construction. Lugged frames are not really welded at the head tube and bottom bracket, they are press fit and brazed. Because of this, you cannot really salvage the head tube or the bottom bracket, and this makes the frame useless for parts normally. Even the rims are those goofy 27inch size, too big for a mountain bike tire. Because I was planning to hack this granny cruiser into something evil, I would be keeping most of the frame in one piece, so the project was still doable.
We found this classic bike at the dump and turned it into a cool contemporary chopper. "Turn down that devil music, you crazy kids!" I could hear the bike talking to me. I thought I'd better rip it all apart before I start wearing a helmet and worrying about brakes! This photo shows the old fashioned bike before hacking. These styles were easy to find at the dump or at yard sales.
Here is the donor bike, taken apart for chopping. Even though this bike is older than time itself, it came apart very easily, and the chrome parts have only slight surface rust - easy to clean with steel wool. I will be using the entire original bike, as the theme for this chop will be Granny's Nightmare!
This chopper will have long forks and a slightly modified frame when completed. I did not want to change the bike so much that it loses its entire original look - the idea is to make it radical yet show its roots. This photo shows the original forks with both legs amputated right at the crown. It should be easy to build a triple tree from these forks as they are made from heavy mild steel. Back in those days, they knew how to build a bike, not like these young "whipper-snappers" today, sonny.
I used the original fork dropouts, so they were cut leaving enough meat to weld to the new fork legs. Save the original fork legs, though. With those nice curves, it should be easy to integrate them back into the frame for a unique and classy look. Both dropouts should be cut as close to the same length as possible in order to insure wheel alignment.
Since the long forks are the focus of the bike, and the frame adjustments will be based upon them, they are made first. I started with a pair of 4 foot long 1 inch thin walled conduit lengths as shown in the photo. Four feet is plenty long, and if I made them much longer, radical frame manipulation would be necessary in order to prevent the "instant wheelie" effect.
The original fork crown is used as the base of the triple tree. The new fork leg extension tubing will be welded directly to the ends of the crown, so it should be ground slightly to allow for easy welding. Do not take too much metal out, just enough to make a good weld that will cover 1/3 or more of the new tubing's diameter. If you grind too much out, the fork legs will be too narrow for a front wheel, and major warping will occur to the conduit while welding.
Once both fork crowns are ground out, and both fork leg extension tubes are exactly the same length, lay the unit on a flat surface and tack weld both fork legs into place as shown here. Use only one solid tack weld per leg, as you want to be able to align the tubes as the front dropouts are positioned in the next few steps.
Once both fork crowns are ground out, and both fork leg extension tubes are exactly the same length, lay the unit on a flat surface and tack weld both fork legs into place as show. Use only one solid tack weld per leg, as you want to be able to align the tubes as the front dropouts are positioned in the next few steps.
To get the dropouts aligned in the proper place at the ends of the new fork legs, first bolt them to a front wheel as shown in the photo. They should be secured tightly and both at the same horizontal angle. Also, make sure that flattened end that holds the axle is not bent. If it is, then pull it straight with a pair of pliers. The distance between the dropouts is usually 5.5 inches for a front wheel. These old bikes may be even less.
With the fork legs tack welded to the fork crown, and the entire unit laying on a flat surface, place the dropouts onto the fork legs as shown here. First tack weld the dropouts in place, then check alignment visually by looking at the unit from all angles, especially lengthwise. If there is any misalignment, it will be easy to correct at this point with a small hammer. If you are satisfied with alignment, weld the entire fork starting with the dropouts and finishing with the cork crown and legs. Check alignment along the way as you weld.
Once the forks are solidly welded, place them into the frame to have a look at what you have so far. Likely, the bike will seem to lean back too far, and the bottom bracket will be very high. Because of the extreme fork length, the frame has been pulled backwards creating the "skyscraper" style chopper. Although the bike would be rideable in this configuration, and it may indeed suit your style, I decided to lower the bottom bracket a few inches by making a small mod to the frame. Since I planned to remove the top tube and convert the frame from a girl's-style frame, this wasn't a big deal.
The top tube is cut from the frame right at the thick part of the lugs on both the head tube and seat tube as shown. The frame is no longer a girl's frame, in fact it is no longer a frame at all because it would not even hold up to a child's weight like this. I did not cut flush with the tubing due to the lugged frame construction, as this would make a huge mess. I planned to use the thicker part of the lugs to my advantage, as you will soon see below.
A rather lazy way to change the angle of a welded tube is to slice a thin pie shaped wedge out of one side, and then bend the tube towards that side to fill the gap. As shown here, I hack sawed a pie shaped cut into the base of the down tube so it could be bent upwards, reducing the height of the bike. Mild steel is very forgiving, and the bending process will not weaken the metal. After the gap is filled with weld metal, it will actually be stronger than when I started.
Once the down tube was bent upwards to close the gap (easy, wasn't it?), the area was welded solid as shown in the photo. If you made your wedge shaped cut even on both sides of the tube, then the tube will be moved in perfect alignment with the rest of the frame.
I thought it would be cool to use only the original bicycle tubing to make this chopper, and since I had a pair of fork legs from the original bike, I decided to use them to make a nice curved top tube. The fork tubing is actually round tubing that has been squished into an oblong shape. To merge it into the frame, I "un-squished" it in the vice, welded the forks together so I would have a piece long enough to become the new top tube, and a bit left over to fill in the ugly gap on the lower lug.
The un-squished fork tubing was cut to fit in place as a new main tube, and the leftover end was welded as a gusset where the lug stub was left from the original top tube and seat tube. This little curve on the top tube gave the frame a stylish look, and would be the basis for a gas tank style gusset later on in the build.
Now that the frame has been modified, place the bottom bracket about 6 inches lower than it was before. Although the frame is still tall and laid back, this would work well for what I had envisioned. Be careful with the forks at this point, without the top of the triple tree, they would not take much weight. Dude, don't sit on the bike yet!
As you can see in the photo, the wedge shaped clamp will slide along the angled cut, creating a tremendous amount of friction in the fork stem, holding the gooseneck in place. Often you can completely remove the long bolt and still have the wedge stay securely fastened in the fork stem, which is why tapping the bolt head is necessary. Also, there are two common sizes of gooseneck stems, so do not put the smaller size in the larger sized fork stem or you may not get a good lock.
The fork will use the conventional triple tree with a top plate bolted to the top of the fork legs, but with a slight difference - it will include the gooseneck as part of the plate. Rather than making a single plate and then fastening a handle bar clamp to it, I decided to use two smaller plates that will fasten directly to a gooseneck. This way, the original bicycle parts, including the handlebars could be used.
I started by cutting a few inches of 1.5 inch flat bar as shown in the photo. When bolted to the nuts that are welded into the fork tube, these plates will form a cap between the gooseneck and the fork tops as will be shown in the next few steps.
The best way to ensure alignment when welding the triple tree plates and gooseneck is to bolt the two plates as shown here. This is how they will be in the final design. The two plates should be aligned as if they were one single plate. The round area ground away at the ends of each plate will form a joint with the steel gooseneck.
Options for a seat on this chopper are abundant, but what I was looking for was something that would fit the theme of the original granny bike, of course, it had to be butchered into something evil at the same time. Rather than mounting the seat in its natural position, I decided that it should go as close to the rear wheel as possible, putting it just behind the seat tube. To accomplish this silly feat, I welded the seat clamp directly to the plate over the rear wheel.
Once I rode around the block a few times making sure that everything was good, I stripped the bike right back down and painted it using the original deep blue color. I buffed up the chrome parts with some steel wool, and put the bike back together. Considering what this bike once was, it sure looked cool!
Yep, Granny's Nightmare really worked out nice! I even reversed the front fender just to add some more wackiness to the bike, but everything looked great. The front chain ring was replaced with a huge chrome unit from an exercise bike, but other than that and some fresh tires, the whole deal was made from the original granny bike. Hey, I told you it could be done!
The moral of this story - never say a bike cannot be chopped. When you find something in the dumpster, don't think, "Hey, look at that scrap." Instead think, "Dude, this thing will make a sick chop." In fact, just about anything made of steel can be used for parts. See that old blender? Yeah, I can use that!
Granny's Nightmare is a prime example of what can be done by simply modifying what you have and using your twisted imagination to put vision into reality. Now, I better go and hide the chopper before granny gets home from Bingo!
Check Out Some Of Our Featured DIY Chopper Plans...
